Insulin-deficient diabetes has been produced in a sub-human primate model (rhesus monkey), which streptozotocin or total surgical pancreatectomy. These monkeys are matched with controls of the same approximate age, and are studied for appearance of diabetic sequelae due to microvascular or functional abnormalities. Emphasis is placed upon ocular and renal organ function and histopathology. The metabolic and endocrine relationships of insulin-deficient diabetes have been documented and are under study. The breeding colony is studied under controlled breeding conditions, for histocompatibility definition for organ transplant protocols. Islet isolation, culture, and transplantation techniques are under investigation in the monkey and rabbit models. New techniques of immunosuppression are under investigation.